This is a yakitori sauce that's very easy to make. If you make a lot, you can use it for all kinds of food, so it's handy to have stocked.
I always used to use the sauce that's made for grilled eel as yakitori sauce, but as that's a little sweet, I changed my recipe a bit to make a sauce that goes better with yakitori.
Adjust the heat when simmering the ingredients.
Enjoy Japanese food around the world.